The XSetWMProtocols function replaces
the WM_PROTOCOLS property on the specified window with the list of atoms
specified by the protocols argument. If the property does not already exist,
XSetWMProtocols sets the WM_PROTOCOLS property on the specified window
to the list of atoms specified by the protocols argument. The property is
stored with a type of ATOM and a format of 32. If it cannot intern the WM_PROTOCOLS
atom, XSetWMProtocols returns a zero status. Otherwise, it returns a
nonzero status.

XSetWMProtocols can generate BadAlloc and BadWindow
errors.

The XGetWMProtocols function returns the list of atoms stored
in the WM_PROTOCOLS property on the specified window. These atoms describe
window manager protocols in which the owner of this window is willing
to participate. If the property exists, is of type ATOM, is of format 32,
and the atom WM_PROTOCOLS can be interned, XGetWMProtocols sets the
protocols_return argument to a list of atoms, sets the count_return argument
to the number of elements in the list, and returns a nonzero status. Otherwise,
it sets neither of the return arguments and returns a zero status. To release
the list of atoms, use XFree.